Effect of mineral fertilizers on sorghum crop yields in the southern forest-steppe of Western Siberia

Abstract

The results of studying the productivity of sorghum crops under different conditions of mineral nutrition on meadow-chernozem soil of the southern forest-steppe of Western Siberia are presented. The study was conducted in 2019–2022 in the Omsk region as part of a long-term stationary field experiment. The soil of the experimental plot is meadow-chernozem moderately deep heavy loamy soil. The arable horizon is characterized by neutral reaction of the soil solution (pH 7.0–7.2). The scheme of the experiment is two-factor, includes application of nitrogen (N0, 30, 60) and phosphorus (P0, 60) mineral fertilizers before sowing sorghum crops. The dynamics of moisture content in the meter soil profile is closely related to the hydrothermal conditions of vegetation periods. In the most wetted year of 2019, the soil profile had a more stable and uniform moisture content, especially in the second half meter. In subsequent years, the atmospheric moisture deficit was clearly manifested in the content of total moisture both along the soil profile and in time. Drying out of the meter profile even in the initial growing season was observed in 2022, which can be considered as a result of low residual moisture in the preceding, also dry, season. In the control, mineral nutrition was limited by the low content of mobile phosphorus. The studies have shown that in conditions of insufficient and unstable moisture, typical for the south of Western Siberia, it is advisable to cultivate sorghum crops with high responsiveness to the use of mineral fertilizers in field fodder production. In the average of two years, the maximum yield of green mass of sugar sorghum on intensive background was 21.07 t/ha, sorghum-sudangrass hybrid – 16.62 t/ha, which is higher than the control by 47.2 and 62.7%, respectively. The most effective was the complex application of mineral fertilizers, which provided an increase in dry matter content of sugar sorghum from 3.97 to 6.08 t/ha (53.0%), sorghum-sudangrasas hybrid – from 2.81 to 4.73 t/ha (68.3%).